The goal of this research is to characterize the electrophysiological phenotypes of sensory and cognitive processing in individuals with Williams Syndrome (WS) and to link variability in the expression of these phenotypes to variability in brain structure, neurocognitive and genetic profiles as determined in projects I-5, respectively. To this end, event-related potentials (ERPs) will be recorded from 32 channels to examine the timing and topography of brain activity linked to 1) differential activation of the dorsal and ventral visual streams, 2) the effects of emotion on processing facial expressions and verbal declarative memory systems, and 3) the organization of semantic and syntactic processing in auditory sentences. These studies are linked with and depend upon the findings from projects I and III. Behavioral (accuracy and reaction times) and ERP data from these experiments will be compared with behavioral measures from similar paradigms and standardized tests described in Project V. Variability in ERP amplitudes will also be compared with that individual's measurement of brain structure for the specific areas of the brain known to mediate that function (in conjunction with Project III), e.g. variability in the latency amplitude and distribution of ERPs linked to differential activation of the dorsal versus ventral visual streams will be compared with measurements of brain regions known to mediate dorsal versus ventral visual processing. The topography of ERPs linked to visual and emotional processing will be compared with the topography of brain activity in the fMRI studies using the same paradigms. Links between abnormal brain function and genetic profiles (Project I) will be conducted by characterizing patterns of activity typical of individuals with WS with a full deletion and comparing these patterns with ERPs from individuals with different genetic profiles such as atypical deletions or parent of origin of the deletion for WS. More generally, these findings in turn will be elucidated by information regarding histochemical and cytoarchitectonic abnormalities in the WS brain (Project IV).